However if the capture was explicit and any valid target could be used as a capture variable then I could express this cleanly:

def update_point_3d(p: Point3d, pt):
    match pt:
        case (p.x=, p.y=):
            pass
        case Point2d(p.x=, p.y=):
            pass
        ...

I like this proposal, using = to explicitly specify when capturing.  I see it as a big improvement over the current PEP where dotted names are never assigned to and non-dotted names usually are.  It also leads directly to an alternate proposal for the wildcard pattern: a "=" not prefaced with an lvalue.  This has the benefit of having no conflict with i18n, etc.

Explicit is better than implicit,

/arry